When it rains, it floods: Part 2

“God created the world, but the Dutch created Holland.”

The Netherlands is uniquely positioned to give some real talk about flooding. As a Dutch friend put it, flooding is really the only natural disaster to affect the NL at great length, and this friend is terrified of them. The region’s entire existence depends on how well they control flood waters, so the Dutch have learned how to do it pretty damn well.

How well is damn well? Let’s consider the Randstad.

The Randstad is a conurbation of the NL’s 4 largest cities—Amsterdam, Rotterdam, The Hague, Utrecht—and is one of the most important economic and industrial centers of Europe. Rotterdam is the largest seaport in Europe, and Amsterdam’s Schiphol airport is a major hub in this part of the world. A large majority of the Randstad is also below sea level. It’s no small feat that the NL has managed to control water so well as to permit the growth and continued existence of such a regional powerhouse.

The centuries-long history of Dutch flood control is interesting, and I’ve had quite the time trying to distill it to its finer points. Some of the best, most classic tools in the Flood Mitigation Shed come directly from the Dutch: the polder, the canal (kanaal or gracht), the sluice (sluis), and, most crucially, the dike (dijk). The Dutch use an impressive dike typology, ranging from sea dikes to river dikes to emergency dikes. But to me the more interesting parts of how the Dutch take on floods are their modern solutions.

Modernity, in this case, begins in the late 19th century when the Dutch decided to completely close off the Zuiderzee, a tempestuous bay that drowned entire communities over the course of (at least) a millennium. The Zuiderzee Works, paired with the Delta Works projects, are one of the Seven Wonders of the Modern World, a list the American Society of Civil Engineers in 1994 dubbed the “greatest civil engineering achievements of the 20th century.”

Both endeavors are a series of projects meant to keep North Sea storm surges from flooding the coastal regions. This is a distinction from last entry, which discusses some the measures the Tokyo area has taken to mitigate river flooding. The challenges are logistically and topographically different. But in the NL, the sea is the real foe, an often grumpy animal who gobbles coastline and lowlands at will. And to keep the sea out in the biggest and best way they could, the Dutch had to do some ingenious engineering on a major scale.

The Zuiderzee (“Southern Sea,” a deceptive name as it’s in the north of the country) was a large but shallow bay, counting about 2,000 sq. miles but only 15 feet of depth. Those dimensions meant disaster when the sea churned up inland-bound storm surges. After a particularly brutal winter storm in 1916 that sent sea water floating over the existing dikes of the Zuiderzee, people rallied behind civil engineer Cornelius Lely’s plan to 1) close off the bay with one massive dike, and 2) use windmills and pumps to create polders of dry land.

It was a crazy plan, and nothing like it had ever been done before. But it worked.

Map by Wikimedia user Scipius.

Up went the Afsluitdijk, a 20-mile-long, 23-foot-tall, nearly 300-foot-wide dike whose 1932 completion was, in Dutch fashion, ahead of schedule. The Zuiderzee had become the artificial lakes IJssel and Marker, which are separated by another large dike.

Within these new lakes, large polders were demarcated by terps and then drained, creating enough new land for an entire new province: Flevoland was officially incorporated in 1986, and contains the world’s largest artificial island.

The Zuiderzee Works have yet to fail.

The Delta Works are a more recent iteration of Dutch flood engineering. Though the first projects broke ground (or water?) in 1950, the country redoubled their efforts in 1953 after a massive and violent winter storm on the North Sea flooded coastal areas of England, Scotland, Belgium, and the southwestern part of the NL, far from the Zuiderzee Works. The disaster was the catalyst for a national conversation about the emergency evacuation system and dike networks, both of which failed the affected localities.

Simply put, the Delta Works were built to protect the Rhine-Meuse-Scheldt river delta from the sea’s storm surges. The whole scheme shortened the coastline in the delta, allowing greater mechanical control for closing off the delta from incoming storm surges in an emergency, and reducing the total number of dikes needed for adequate protection.

This map is a general overview of the major projects:

Image by OpenStreetMap.org user Classical Geographer.

That’s a lot of dams for a storm surge to break. The Delta Works were officially completed in 1997, but the Dutch government acknowledges that improvements will have to be made as sea levels rise. Nothing is ever really over, is it?

Interestingly, the Dutch consider river flooding to have a longer evacuation time than sea flooding, and in fact determined that comprehensive evacuation from coastal areas isn’t even an option. This challenges my south-central Texan perception that flash flooding is a mainly riparian affair.

To be fair, the country’s rivers do flood, or at least get high enough to spur local evacuations, which has led to a far more recent series of flood mitigation projects called Room for the River. These projects are a bit less monumental than the Zuiderzee and Delta Works, and, as the umbrella project name belies, focus on river flooding.

Most notable among these projects, though, is Room for the Waal. The River Waal flows through the heart of Nijmegen, the NL’s oldest town, where it bends and bottlenecks and causes occasional alarm during and after heavy rain events. Room for the Waal called for relocating a dike 350 meters inland and digging a new side channel for the river, which created a new island (and three new bridges) to be used as an urban park with “with possibilities for recreation, culture, water and nature”

“After 800 years of building dikes, we’ve been making them higher and higher. But if something goes wrong, the damage will be greater… We need to remain flexible in adapting to climate change, so now we try to remove the bottlenecks.”

Room for the Waal exemplifies something I, an American urbanist living in the NL, the am thrilled by: mandatorylocal control of a federal project. For Nijmegen to get funding for the river improvements it needed, the people had to create their own vision for their new waterfront; the federal government offered to pick up the tab once the plan was cohesive.

Nijmegen city staff put together a 4-minute video in 2010 to help explain the changes of the new plan. There isn’t a word of English, but you don’t need to know Dutch to appreciate the images of then-daily life and digital renderings of the proposed plans. (Plus Dutch is kind of fun to listen to anyway.)

And here’s a drones-eye-view video from November 2014 showing the plan’s progress.

Room for the River could be where routinely flooded places in Texas can glean the more appropriate lessons about flood mitigation rather than the massive undertakings on the North Sea. I’m not suggesting we carve islands out of the clays and loams of the Blanco River or erect dikes around Buffalo Bayou, necessarily (though I think the latter could be a possibility, but I’m no engineer).

But beyond the scope of engineering for 100-, 500-, and 10,000-year floods, the NL made history last week when The Hague District Court ruled the Dutch government must take measures to cut the country’s greenhouse gas emissions by 25% by 2020 (whereas the current track will have emissions cut by 17%). A large group of concerned citizens sued the government—and the judge agreed with them—regarding the “legal obligation to protect its people against looming dangers, including the effects of climate change on this low-lying country.” Rising sea levels are a clear threat in the coming decades to many places around the world, and this legal decision could have great ramifications for them, too. Even a judge in Seattle has since ordered the Washington State Department of Ecology to consider a group of teens’ petition “to develop policy-limiting carbon dioxide emissions based on best available science.”

To dovetail with Part 1: What will Texans learn from the Memorial Day floods? What can we change about our communities and their attitudes toward the environment? How much collectivism will our culture of fierce individualism permit, and how do we feel about that when faced with what could be a soggy and very hot 21st century? What should we demand from state and regional government and industry? As much as we may want to, we cannot strike a bargain with nature, only a balance.

3 Comments

Great article, Kelly! I think we as a country have a lot to learn from the Dutch when it comes to flood mitigation and resiliency. New Orleans comes to mind for me; if we had a more Dutch approach, perhaps the Crescent City wouldn’t be sinking.